“What’s yellow and square?”/“A tomato in disguise.”

A tomato riddle is:
 
Q: What’s yellow and square?
A: A tomato in disguise.
 
The riddle has been cited in print since at least 2004. “What’s blue and looks like a tomato?”/“A red tomato in disguise” is a similar tomato riddle.
   
   
Google Books
1001 Cool School Yard Jokes
By Glen Singleton, Nicolas Brasch and Barbara Whiter
Heatherton, Victoria: Hinkler Books
2004
Pg. 76:
What’s yellow and square?
A tomato in disguise.
 
Twitter
Grossy McGross-gross
‏@upinyourbox
what’s yellow and square? ...a tomato in disguise
10:03 PM - 17 Dec 2009
 
Twitter
Sal
‏@Salim_A_
What is square and yellow?....a tomato in disguise 😊
6:23 AM - 4 Jan 2013
 
Teitter
Crap Jokes
‏@TheCrapJoker
Q) What’s yellow and square?
A) A tomato in disguise.
9:32 AM - 8 Aug 2015
 
Twitter
Shit Jokes
‏@ShitJokes
What’s yellow and square?
A tomato in disguise.
3:38 PM - 30 Nov 2016